Thermal frame section with offset dual skip debridgings

ABSTRACT

An architectural thermal break section includes an elongate heat-conductive part having spaced elongate first and second side portions and having an elongate bridge portion extending between the side portions, the bridge portion having therethrough elongate first, second and third lengthwise slots, the second slot having at respective ends thereof first and second end portions which are transversely spaced from and overlap in the lengthwise direction respective end portions of the first and third slots. The break section further includes a lengthwise strip of a thermal barrier material which extends between and is fixedly coupled to each of the first and second side portions. A method of making the break section includes the steps of extruding a metal to form the heat-conductive part, thereafter applying the thermal barrier material to the heat-conductive part, and thereafter machining the slots in the bridge portion of the heat-conductive part.

FIELD OF THE INVENTION

This invention relates to architectural thermal barrier sections and,more particularly, to an improvement in skip-debridging a bridge portionof an extrusion which extends between two spaced side portions of theextrusion.

BACKGROUND OF THE INVENTION

As the costs of energy sources such as oil increase, increasing emphasisin architectural design has been placed on the reduction of heat flowbetween the inside and outside of buildings. This is particularly truewith respect to the casings for glass windows and glass doors.

For example, a popular conventional technique is to make a window sash(the part that contains the glass) from architectural components whicheach have separate spaced aluminum side portions rigidly connected toeach other by a thermal barrier material such as a polyurethane polymerresin. The aluminum side portions provide strength and rigidity, whilethe thermal barrier material substantially avoids a transfer of heatbetween the side portions. A very common method of making such acomponent is to initially extrude a single integral piece of aluminumwhich includes not only the side portions but also a bridge portionextending between the side portions in order to rigidly interconnectthem. A liquid thermal barrier material is then poured into an upwardlyopen channel defined in part by the bridge portion, after which thethermal barrier material is cured until it is hard and rigidlyinterconnects the first and second portions. The thermal barriermaterial typically tends to adhesively bond to the aluminum extrusion asit cures. Then, a conventional milling tool is used to mill away thematerial of the bridge portion so that the first and second portionsliterally become two separate parts which are rigidly interconnectedonly by the thermal barrier material. In other words, a single elongateslot extending the full length of the component is milled into thebridge portion. This technique is disclosed, for example, in Gordon U.S.Pat. No. 4,463,540, the disclosure of which is hereby incorporatedherein by reference.

While the architectural component resulting from this approach has beengenerally adequate for its intended purposes, it has not beensatisfactory in all respects. One particular problem relates toresistance to shear stresses, in that the two spaced aluminum portionsare held against lengthwise sliding with respect to each other primarilyby the adhesive bond which is present between each and the thermalbarrier material. The strength of this bond can vary widely fromcomponent to component, and in a production situation it has proveddifficult to reliably and consistently achieve bond strengths withinacceptable limits. One conventional technique for dealing with thisproblem is known as "skip debridging". In particular, instead of millinginto the bridging portion a single slot which extends the full length ofthe extrusion, several spaced slots which extend along a commonlengthwise line are milled into the bridging portion. The adjacent endsof each adjacent pair of slots are spaced from each other by a distancewhich is approximately one tenth to one twentieth of the overall lengthof each slot. Thus, in the region between the adjacent ends of adjacentslots, a section of the bridging portion is left to extend between theside portions of the extrusion so as to serve as a connecting portion.

Since this technique leaves small integral aluminum connecting portionsextending between the side portions of the extrusion at spaced locationsalong the length of the extrusion, the connecting portions rigidly andreliably resist any relative lengthwise movement of the side portions,independently of the strength of the adhesive bonds between the thermalbarrier material in each side portion. However, a disadvantage is thatthe aluminum connecting portions which extend between the side portionsallow an undesirably large degree of thermal energy transfer between theside portions.

Thus, milling a single slot in the bridging portion along the fulllength of the extrusion provides excellent thermal separation butunpredictable strength against shear forces, whereas providing periodicinterruptions in the slot provide a reliable resistance to shear forcesbut significantly degrades the thermal separation.

Therefore, an important object of the present invention is therefore toprovide an improvement in debridging which assures a high degree ofthermal separation while simultaneously providing a reliable high degreeof resistance to shear forces.

A further object is to provide such an improvement in debridging whichdoes not increase the complexity or cost of the resulting architecturalcomponent, and which does not significantly increase the cost orcomplexity of the process for manufacturing the component.

SUMMARY OF THE INVENTION

The objects and purposes of the invention, including those set forthabove, are met according to the invention by providing a method whichincludes the steps of fabricating an elongate heat-conductive part whichextends in a lengthwise direction, which has elongate first and secondside portions spaced transversely from each other, and which has abridging portion extending transversely between the side portions,thereafter applying to the heat conductive part a thermal barriermaterial which is fixedly coupled to each of the first and second sideportions, and thereafter machining through the bridge portion elongatefirst, second and third slots which each extend approximately parallelto the lengthwise direction, the second slot having first and second endportions which are spaced in the transverse direction from and overlapin the lengthwise direction respective end portions of the first andthird slots.

The objects and purposes of the invention are also met by providing anarchitectural thermal break section which includes an elongateheat-conductive part having spaced first and second side portionsextending lengthwise thereof and having a bridge portion extendingbetween the side portions, the bridge having therethrough elongatefirst, second and third slots which extend approximately lengthwise, thesecond slot having at respective ends thereof first and second endportions which are spaced in the transverse direction from and overlapin the lengthwise direction respective end portions of the first andthird slots, respectively, the thermal break section further including alengthwise strip of a thermal barrier material which extends between andis fixedly coupled to each of the first and second side portions andwhich contacts the bridge portion.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the inventive method and apparatus will be described indetail hereinafter with reference to the accompanying drawings, inwhich:

FIG. 1 is a sectional end view of an architectural thermal break sectionaccording to a preferred embodiment of the invention, the extrusionbeing shown before parts of a bridging portion are removed;

FIG. 2 is a sectional end view similar to FIG. 1 but showing the thermalbreak section after the parts of the bridging portion have been removed;and

FIG. 3 is a fragmentary perspective view of the thermal break sectionshown in FIG. 2.

DETAILED DESCRIPTION

Referring to FIG. 3, an architectural thermal break section 10 accordingto the present invention includes an elongate aluminum extrusion 11 andan elongate strip 12 of a thermal barrier material.

Referring to FIG. 1, the aluminum extrusion 11 of the preferredembodiment will now be described, but it will be recognized that theshape of the extrusion 11 may vary widely according to the requirementsof different applications, and the invention is not limited to anyparticular shape of the extrusion 11. The extrusion 11 is a singleintegral structural part, which includes a planar bridge portion 16extending between first and second side portions 17 and 18.

The first side portion 17 includes a horizontal wall portion 21 which iscoplanar with the bridge portion 16, an upright wall portion 22 whichextends upwardly from the inner end of wall portion 21, a flange 23which extends inwardly from the upper end of upright wall portion 22,and a lip 24 which extends downwardly from the inner end of flange 23.Similarly, the side portion 18 includes a horizontal wall portion 26which is coplanar with the bridge portion 16, an upright wall portion 27which extends upwardly from the inner edge of the wall portion 26, aflange 28 which extends inwardly from an upper end of the upright wallportion 27, and a downwardly projecting lip 29 provided at the inner endof the flange 28. The bridge portion and the upright wall portions 22and 27 define an upwardly open channel or pocket 32 which extends thefull length of the extrusion 11 and which has disposed in it the thermalbarrier material 12.

Still referring to FIG. 1, after the extrusion 11 is fabricated, it isoriented as shown in FIG. 1 and then the thermal barrier material, forexample a polyurethane polymer resin, is poured in liquid form into thechannel or pocket 32 until it is approximately level with the flanges 23and 28. The thermal barrier material 12 is then cured to a solid state,whereby it adhesively bonds to the aluminum extrusion and forms a rigid,heat-insulating block which extends between the first and secondportions 17 and 18 of the extrusion 11. The lips 24 and 29 on theflanges 23 and 28 are embedded in the thermal barrier material 12,thereby helping to resist twisting movements of the portions 17 and 18relative to the thermal barrier material 12 and causing the thermalbarrier material 12 to contribute to a substantially rigidinterconnection with each of the side portions 17 and 18.

After the thermal barrier material 12 has fully cured, and referring toFIGS. 2 and 3, a plurality of elongate slots 36-39 are milled into thebridge portion 16 of the extrusion 11, for example using a conventionalmilling tool. The slots 36-39 each extend completely through the bridgeportion 16, and are parallel to each other and extend lengthwise of theextrusion 11. The slots 36 and 37 extend along a common first line 41and are spaced from each other along this line, the distance 43 betweenthe adjacent ends of the slots 36 and 37 being approximately one tenthto one twentieth of the full length of one of the slots, for example asshown at 44 for slot 37. Similarly, the slots 38 and 39 extend along acommon second line 42 which is parallel to and offset transversely fromthe first line 41. The adjacent ends 46 and 47 of these slots are spacedfrom each other, and disposed approximately halfway between the ends ofthe slot 37. Thus, the illustrated end portion of slot 36 overlaps oneend portion of slot 38 in a lengthwise direction, the opposite endportion of slot 38 overlaps one end portion of slot 37 in a lengthwisedirection, the opposite end portion of 37 overlaps one end portion ofthe slot 39 in a lengthwise direction, and so forth. The slots 36 and 37are separated from the slots 38 and 39 in a transverse direction by acentral strip 52 of the bridge portion 16, the strip 52 having a widthapproximately equal to the width of slots 36-39, and extending the fulllength of the extrusion. The strip 52 is connected to the side portion17 by connecting portions 51 of the bridge portion 16, and to the sideportion 18 by similar connecting portions 53, the connecting portions 51being intermediate two connecting portions 53 in a lengthwise direction.

Due to the offset arrangement of the connecting portions 51 and 53, heatattempting to flow from the extrusion side portion 17 to the extrusionside portion 18 must flow through the connecting portion 51 between theends of the slots 38 and 39 extending along line 42, along the narrowcentral strip 52 disposed between slot 37 and slot 38 or 39, and thenthrough one of the connecting portions 53. This circuitous transfer pathalong portions 51-53 of the extrusion 11, each having a relatively smallcross-sectional area, facilitates minimization of the transfer of heatbetween the side portions 17 and 18 of the extrusion 11, while providingdependable resistance to shear forces exerted on the side portions 17and 18 and urging relative lengthwise movement of them.

Although a single preferred embodiment of the invention has beendescribed in detail for illustrative purposes, it will be recognizedthat there are variations or modifications of the disclosed embodiment,including the rearrangement of parts, which lie within the scope of theappended claims.

The embodiments of the invention in which an exclusive property orprivilege are claimed are as follows:
 1. An architectural thermal breaksection, comprising: an elongate heat-conductive part extending in alengthwise direction, having elongate first and second side portionswhich extend in said lengthwise direction and are spaced from each otherin a transverse direction perpendicular to said lengthwise direction,and having an elongate bridge portion extending in said lengthwisedirection and extending in said transverse direction between said firstand second side portions, said bridge portion having therethroughelongate first, second and third slots which extend approximatelyparallel to said lengthwise direction, said second slot having atrespective ends thereof first and second end portions which are spacedin said transverse direction from and overlap in said lengthwisedirection respective end portions of said first and third slots,respectively; and including a strip of a thermal barrier material whichextends in said lengthwise direction and which is fixedly coupled toeach of said first and second side portions of said heat-conductivepart, said strip of thermal barrier material being disposed against saidbridge portion of said heat-conductive part.
 2. An architectural thermalbreak section according to claim 1, wherein said first and third slotseach extend along a first line and are spaced from each other along saidline, and wherein said second slot extends along a second line which isparallel to and spaced in said transverse direction from said firstline.
 3. An architectural thermal break section of claim 2, wherein eachsaid slot has a predetermined width, and wherein said first and secondend portions of said second slot are spaced respectively from said endportions of said first and third slots by a distance approximately equalto said predetermined width.
 4. An architectural thermal break sectionof claim 2, wherein a part of said bridge portion disposed between saidadjacent end portions of said first and third slots is disposedapproximately intermediate said end portions of said second slot withrespect to said lengthwise direction.
 5. An architectural thermal breaksection of claim 2, wherein said adjacent end portions of said first andthird slots are spaced in said lengthwise direction from each other by adistance which is in the range of one tenth to one twentieth of a lengthof said second slot.
 6. An architectural thermal break section of claim2, wherein said bridge portion has provided therethrough an elongatefourth slot extending in said lengthwise direction, said second andfourth slots each extending along said second line and being spaced fromeach other along said line, said fourth slot having an end portion whichis spaced in said transverse direction from and overlaps in saidlengthwise direction an end portion of said third slot which is remotefrom said first slot.
 7. An architectural thermal break section,comprising an elongate heat-conductive component extending in alengthwise direction, said component including elongate first and secondside portions which extend in said lengthwise direction and are spacedfrom each other in a transverse direction substantially perpendicular tosaid lengthwise direction, including a central strip disposed betweenand spaced in said transverse direction from each of said first andsecond side portions, said central strip extending in said lengthwisedirection, including a first connecting portion extending in saidtransverse direction between said first side portion and said centralstrip, and including a second connecting portion extending between saidsecond side portion and said central strip, said first and secondconnecting portions being spaced from each other in said lengthwisedirection; said break section further including a strip of a thermalbarrier material which extends between and is rigidly coupled to each ofsaid first and second side portions, and which contacts said centralstrip and said first and second connecting portions.
 8. An architecturalthermal break section of claim 7, including a third connecting portionextending between said first side portion and said central strip at alocation spaced in said lengthwise direction from said first connectingportion, said second connecting portion being positioned substantiallyintermediate of said first and third connecting portions with respect tosaid lengthwise direction.
 9. A method of making an architecturalthermal barrier section, comprising the steps of fabricating an elongateheat-conductive part which extends in a lengthwise direction, which haselongate first and second side portions extending in said lengthwisedirection and spaced from each other in a transverse directionsubstantially perpendicular to said lengthwise direction, and which hasa bridging portion extending in said transverse direction between saidside portions; thereafter applying to said heat-conductive part athermal barrier material which extends lengthwise thereof and whichextends in said transverse direction between and is fixedly coupled toeach of said first and second side portions; and thereafter machiningthrough said bridge portion elongate first, second and third slots whicheach extend approximately parallel to said lengthwise direction, saidsecond slot having first and second end portions which are spaced insaid transverse direction from and overlap in said lengthwise directionrespective end portions of said first and third slots.
 10. A method ofclaim 9, wherein said fabricating step is carried out by the step ofextruding a metal to form said heat-conductive part.
 11. A method ofclaim 9, wherein said fabricating step includes the step of creating insaid heat-conductive part a channel, and said step of applying saidthermal barrier material includes the steps of pouring said thermalbarrier material in liquid form into said channel and thereafterfacilitating hardening of said thermal barrier material.